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ARC: [plat-eznps] handle extra aux regs #2: kernel/entry exit 

Preserve eflags and gpa1 aux during entry/exit into kernel as these
could be modified by kernel mode

These registers used by compare exchange instructions.
  - GPA1 is used for compare value,
  - EFLAGS got bit reflects atomic operation response.

EFLAGS is zeroed for each new user task so it won't get its
parent value.

Signed-off-by: Liav Rehana <liavr@mellanox.com>
Signed-off-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Liav Rehana 2017-06-15 11:44:00 +03:00 committed by Vineet Gupta
parent 5b2189ab6e
commit 28923f6b74
3 changed files with 33 additions and 0 deletions
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24
arch/arc/include/asm/entry-compact.h
View File

@ -192,6 +192,12 @@
PUSHAX lp_start
PUSHAX erbta
#ifdef CONFIG_ARC_PLAT_EZNPS
.word CTOP_INST_SCHD_RW
PUSHAX CTOP_AUX_GPA1
PUSHAX CTOP_AUX_EFLAGS
#endif
lr r9, [ecr]
st r9, [sp, PT_event] /* EV_Trap expects r9 to have ECR */
.endm
@ -208,6 +214,12 @@
* by hardware and that is not good.
*-------------------------------------------------------------*/
.macro EXCEPTION_EPILOGUE
#ifdef CONFIG_ARC_PLAT_EZNPS
.word CTOP_INST_SCHD_RW
POPAX CTOP_AUX_EFLAGS
POPAX CTOP_AUX_GPA1
#endif
POPAX erbta
POPAX lp_start
POPAX lp_end
@ -265,6 +277,12 @@
PUSHAX lp_end
PUSHAX lp_start
PUSHAX bta_l\LVL\()
#ifdef CONFIG_ARC_PLAT_EZNPS
.word CTOP_INST_SCHD_RW
PUSHAX CTOP_AUX_GPA1
PUSHAX CTOP_AUX_EFLAGS
#endif
.endm
/*--------------------------------------------------------------
@ -277,6 +295,12 @@
* by hardware and that is not good.
*-------------------------------------------------------------*/
.macro INTERRUPT_EPILOGUE LVL
#ifdef CONFIG_ARC_PLAT_EZNPS
.word CTOP_INST_SCHD_RW
POPAX CTOP_AUX_EFLAGS
POPAX CTOP_AUX_GPA1
#endif
POPAX bta_l\LVL\()
POPAX lp_start
POPAX lp_end

5
arch/arc/include/asm/ptrace.h
View File

@ -19,6 +19,11 @@
#ifdef CONFIG_ISA_ARCOMPACT
struct pt_regs {
#ifdef CONFIG_ARC_PLAT_EZNPS
unsigned long eflags; /* Extended FLAGS */
unsigned long gpa1; /* General Purpose Aux */
#endif
/* Real registers */
unsigned long bta; /* bta_l1, bta_l2, erbta */

4
arch/arc/kernel/process.c
View File

@ -234,6 +234,10 @@ void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
*/
regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS;
#ifdef CONFIG_EZNPS_MTM_EXT
regs->eflags = 0;
#endif
/* bogus seed values for debugging */
regs->lp_start = 0x10;
regs->lp_end = 0x80;